1. Field of the Invention
The present invention relates to a rechargeable battery module, and more particularly, to a battery module that is capable of effectively managing the variation of intervals between unit batteries.
2. Discussion of the Background
Generally, rechargeable batteries can be charged and discharged repeatedly so that they can be used many times. In particular, rechargeable batteries that have only one battery is cell are mainly used for various small portable electronic devices such as cellular phones, laptop computers, cameras, and camcorders. High-capacity rechargeable batteries, hereinafter referred to as “battery modules” are formed by connecting a plurality of battery cells, hereinafter referred to as “unit batteries.” Battery modules are mainly used as power sources for motors of hybrid electric vehicles (HEV), electrical vehicles (EV), etc.
Each of the unit batteries that constitute a battery module include an electrode assembly comprising a positive plate, a negative plate, and a separator that is interposed therebetween. The unit batteries further include a case to house the electrode assembly, a cap assembly for closing the case, and a positive terminal and a negative terminal that protrude from the cap assembly and are coupled with the positive plate and the negative plate, respectively.
Further, when the unit batteries have a rectangular box shape, a positive terminal and a negative terminal protrude upward from the cap assembly. They are arranged to alternate with a positive terminal and a negative terminal of an adjacent unit battery. The positive terminals and the negative terminals are threaded and a connecting terminal is connected between the threaded positive terminals and negative terminals with nuts, thereby forming a battery module.
Since the battery module is constructed by connecting multiple unit batteries together, the intervals between the unit batteries may not be uniform. When partition walls are formed between the unit batteries, the variation in space between the respective unit batteries further increases due to installation errors and variations in the partition walls.
Therefore, in order to manage the variation in intervals between the unit batteries, a conventional battery module may include a bent portion that is formed in the middle portion of a connecting terminal for connecting positive terminals and negative terminals that are adjacent to each other.
However, a bent portion also requires sufficient space to install the connecting terminal. Also, the bent portion may be deformed, causing the connecting terminal to be damaged or broken during its installation. In addition, if the bent portion is pressed by an external force, unexpected short-circuiting may occur.